PIV SDRAM vs PIV DDR vs XP DDR vs T-Bird SDRAM - HELP!

SUMMARY: The case for an upgrade depends on where you start from – the more current your system, the less the benefit.

Choices – sometimes good, sometimes confusing. If you’re thinking of upgrading and wonder which way to go and what you’ll get, what follows may shed some light on what to consider.

As Ed pointed out HERE, the high-performance end is likely to be quite competitive in 2002 and our long-range plan has been to increase Intel coverage in 2002. To my delight, one of our Intel readers very kindly sent me a PIV and an ACORP motherboard that runs SDRAM. Shortly thereafter, Lucky Star sends me their PIV motherboard that uses DDR (detailed review in the works). I will use these primarily to test PIV heatsinks, but since I had them, I figured I might as well do a few comparisons.

Let’s get this one out of the way first:

PIV: SDRAM vs DDR

PIV Motherboards: Acorp SDRAM vs Lucky Star DDR – 1700 MHz

Benchmark

PIV SDRAM

PIV DDR

% Diff

SiSandra CPU

3190/2047

3187/2055

NA

SiSandra MM

6723/8261

6724/8266

NA

SiSandra Memory

681/682

1102/1228

-38/-44%

Quake

149.1/144.0

182.3/176.5

-18/-18 %

3D Mark 2001

3568

4126

-14%

Lucky Star P4A845D vs Acorp 4S845A

Let’s call this the RAMBUS Performance Tax and leave it at that – obviously, if you are upgrading, run – don’t walk – away from the PIV SDRAM option.

OK, let’s get to some real choices.

If you were walking in to COMP USA, for example, and saw two systems side by side, one a PIV 1700 and an XP 1700+, you might think they were comparable systems. The salesman whispers in your ear “AMD is fooling you – it only runs at 1466 MHz and the PIV at 1700 MHz – more is better!”

“DAMN!” you say, “Show me how much AMD is fooling us – let’s run a few benchmarks!” and you find:

PIV 1700 vs XP 1700+

Benchmark

XP 1700+

PIV 1700

% Diff

SiSandra CPU

4109/2033

3187/2055

29/-1%

SiSandra MM

8170/9402

6724/8266

22/14%

SiSandra Memory

793/897

1102/1228

-28/-27%

Quake

190.3/188.2

182.3/176.5

4/7%

3D Mark 2001

4506

4126

9%

Lucky Star P4A845D vs Shuttle AK31

Well now, a real interesting set of benchmarks! (If you were AMD, wouldn’t you de-emphasize MHz?) What hits you in the eye is the almost 30% difference in bandwidth in favor of the PIV. However, even with this disadvantage, the AMD’s XP1700+ manages to eke out some modest (probably invisible on the screen) gains vs the PIV 1700.

But since you know more than the average “walk into COMP USA” type, you want to “peel back the layers” of this onion, so you ask to and run both systems at the SAME SPEED:

XP and PIV @ 1400 MHz

Benchmark

XP @ 1400

PIV @ 1400

% Diff

SiSandra CPU

3930/1929

2617/1683

50/15%

SiSandra MM

7797/8972

5525/6789

41/32%

SiSandra Memory

802/859

1101/1223

-27/-30%

Quake

184.9/182.9

161.8/161.7

14/13%

3D Mark 2001

4751

3766

26%

Lucky Star P4A845D, 14 x 100 FSB, vs Shuttle AK31, 10.5 x 133 FSB.

Double digit differences are significant and something you might see on screen. The salesman screams “LIES all LIES! I can run them both at 1400 MHz and you’ll see a different picture!” He takes you to the back room and shows you a PIV running at 13 x 130 FSB (1400 MHz) with this comparison:

XP and PIV @ 1400 MHz

Benchmark

XP 10.5×133

PIV 13×130

% Diff

SiSandra CPU

3930/1929

3179/2043

24/-6%

SiSandra MM

7797/8972

6714/8250

16/9%

SiSandra Memory

802/859

1096/1237

-27/-31%

Quake

184.9/182.9

218.0/211.9

-15/-14%

3D Mark 2001

4751

4274

11%

Lucky Star P4A845D, 13 x 130 FSB, vs Shuttle AK31, 10.5 x 133 FSB.

Of course, what he neglects to tell you is that the PIV is running the PCI bus 30% faster¹ than spec while the XP is not, and that the PIV he is using is an engineering sample with an adjustable multiplier (not available to the public) – but minor details.

You then say “I have a T-Bird 1400 @ 1650 (11×150), Iwill KK266+ using SDRAM – let’s see how it stacks up:

“This is true, and I’ll probably get a 10-20% gain over the T-Bird. The REAL question – Can I see it on screen?”

Fade out on the salesman’s blank stare.

So What To Do?

Depends:

If your system is not more than one year old, why bother?;

If you MUST upgrade now and you are not into overclocking, then a similarly rated PIV or XP based DDR system will do you fine;

If you are into performance, wait for the 0.13 micron CPUs;

For the avid overclocker, I think it comes down to this – if you’re OK with varying only FSBs, then Intel; if you want to vary both multiplier and FSBs, then AMD (I like more options than less).

As 2002 unfolds, we will do more testing, but I don’t think you’re going to see a “knockout” CPU from either Intel or AMD. If AMD makes enabling multiplier adjustments all but impossible, it may be a real toss-up.

¹For example, note that Quake at 218.0/161.8 = 35%, roughly in line with the 30% bus increase.

TESTING NOTES: All tests were conducted using 256MB Crucial DDR or SDRAM at 2522 memory settings; in some cases, 3DMark2001 would not run with these settings and was detuned to Normal. Video card was a LeadTek Geforce 2 Pro, 32 MB. SiSoft Sandra benchmarks used the 2001te version, Quake was run at 600 x 480 and 3DMark2001 at 800×600, 16 bit, sound enabled on all motherboards.